A hard coating film has been used for protecting the surface of various image displays including a liquid crystal display device (LCD), an electroluminescence (EL) display device, a plasma display (PD), a field emission display (FED) and the like.
Recently, a flexible display which can maintain display performance even when it is bent like a paper by using a flexible material such as plastic, instead of a conventional glass substrate having no flexibility, gains attention as a next generation display device. In this regard, there is a need for a hard coating film which not only has high hardness and good impact resistance but also has proper flexibility, without curling at the film edges during its production or use.
Korean Patent Application Publication No. 10-2016-0057221 discloses a hard coating composition which comprises an epoxy siloxane resin having a weight average molecular weight of 800 to 30,000, a crosslinking agent containing a compound having an epoxy cyclohexane structure, and a photopolymerization initiator, wherein the hard coating composition exhibits high hardness.
However, in the case of such a hard coating composition with high hardness, there was a problem that curling occurs after curing.